/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/* Some ICMP messages should be passed to the transport protocols. This
   is not implemented. */

#include "lwip/opt.h"

#if LWIP_ICMP			/* don't build if not configured for use in lwipopts.h */

#include "lwip/icmp.h"
#include "lwip/inet.h"
#include "lwip/ip.h"
#include "lwip/def.h"
#include "lwip/stats.h"

void
icmp_input (struct pbuf *p, struct netif *inp)
{
  u8_t type;
  struct icmp_echo_hdr *iecho;
  struct ip_hdr *iphdr;
  struct ip_addr tmpaddr;

  ICMP_STATS_INC (icmp.recv);

  /* TODO: check length before accessing payload! */

  type = ((u8_t *) p->payload)[0];

  switch (type)
    {
    case ICMP6_ECHO:
      LWIP_DEBUGF (ICMP_DEBUG, ("icmp_input: ping\n"));

      if (p->tot_len < sizeof (struct icmp_echo_hdr))
	{
	  LWIP_DEBUGF (ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));

	  pbuf_free (p);
	  ICMP_STATS_INC (icmp.lenerr);
	  return;
	}
      iecho = p->payload;
      iphdr = (struct ip_hdr *) ((u8_t *) p->payload - IP_HLEN);
      if (inet_chksum_pbuf (p) != 0)
	{
	  LWIP_DEBUGF (ICMP_DEBUG,
		       ("icmp_input: checksum failed for received ICMP echo (%"
			X16_F ")\n", inet_chksum_pseudo (p, &(iphdr->src),
							 &(iphdr->dest),
							 IP_PROTO_ICMP,
							 p->tot_len)));
	  ICMP_STATS_INC (icmp.chkerr);
	  /*      return; */
	}
      LWIP_DEBUGF (ICMP_DEBUG,
		   ("icmp: p->len %" S16_F " p->tot_len %" S16_F "\n", p->len,
		    p->tot_len));
      ip_addr_set (&tmpaddr, &(iphdr->src));
      ip_addr_set (&(iphdr->src), &(iphdr->dest));
      ip_addr_set (&(iphdr->dest), &tmpaddr);
      iecho->type = ICMP6_ER;
      /* adjust the checksum */
      if (iecho->chksum >= htons (0xffff - (ICMP6_ECHO << 8)))
	{
	  iecho->chksum += htons (ICMP6_ECHO << 8) + 1;
	}
      else
	{
	  iecho->chksum += htons (ICMP6_ECHO << 8);
	}
      LWIP_DEBUGF (ICMP_DEBUG,
		   ("icmp_input: checksum failed for received ICMP echo (%"
		    X16_F ")\n", inet_chksum_pseudo (p, &(iphdr->src),
						     &(iphdr->dest),
						     IP_PROTO_ICMP,
						     p->tot_len)));
      ICMP_STATS_INC (icmp.xmit);

      /*    LWIP_DEBUGF("icmp: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len); */
      ip_output_if (p, &(iphdr->src), IP_HDRINCL,
		    iphdr->hoplim, IP_PROTO_ICMP, inp);
      break;
    default:
      LWIP_DEBUGF (ICMP_DEBUG,
		   ("icmp_input: ICMP type %" S16_F " not supported.\n",
		    (s16_t) type));
      ICMP_STATS_INC (icmp.proterr);
      ICMP_STATS_INC (icmp.drop);
    }

  pbuf_free (p);
}

void
icmp_dest_unreach (struct pbuf *p, enum icmp_dur_type t)
{
  struct pbuf *q;
  struct ip_hdr *iphdr;
  struct icmp_dur_hdr *idur;

  /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
  q = pbuf_alloc (PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
  /* ICMP header + IP header + 8 bytes of data */
  if (q == NULL)
    {
      LWIP_DEBUGF (ICMP_DEBUG,
		   ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
      pbuf_free (p);
      return;
    }
  LWIP_ASSERT ("check that first pbuf can hold icmp message",
	       (q->len >= (8 + IP_HLEN + 8)));

  iphdr = p->payload;

  idur = q->payload;
  idur->type = (u8_t) ICMP6_DUR;
  idur->icode = (u8_t) t;

  SMEMCPY ((u8_t *) q->payload + 8, p->payload, IP_HLEN + 8);

  /* calculate checksum */
  idur->chksum = 0;
  idur->chksum = inet_chksum (idur, q->len);
  ICMP_STATS_INC (icmp.xmit);

  ip_output (q, NULL,
	     (struct ip_addr *) &(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
  pbuf_free (q);
}

void
icmp_time_exceeded (struct pbuf *p, enum icmp_te_type t)
{
  struct pbuf *q;
  struct ip_hdr *iphdr;
  struct icmp_te_hdr *tehdr;

  LWIP_DEBUGF (ICMP_DEBUG, ("icmp_time_exceeded\n"));

  /* @todo: can this be PBUF_LINK instead of PBUF_IP? */
  q = pbuf_alloc (PBUF_IP, 8 + IP_HLEN + 8, PBUF_RAM);
  /* ICMP header + IP header + 8 bytes of data */
  if (q == NULL)
    {
      LWIP_DEBUGF (ICMP_DEBUG,
		   ("icmp_dest_unreach: failed to allocate pbuf for ICMP packet.\n"));
      pbuf_free (p);
      return;
    }
  LWIP_ASSERT ("check that first pbuf can hold icmp message",
	       (q->len >= (8 + IP_HLEN + 8)));

  iphdr = p->payload;

  tehdr = q->payload;
  tehdr->type = (u8_t) ICMP6_TE;
  tehdr->icode = (u8_t) t;

  /* copy fields from original packet */
  SMEMCPY ((u8_t *) q->payload + 8, (u8_t *) p->payload, IP_HLEN + 8);

  /* calculate checksum */
  tehdr->chksum = 0;
  tehdr->chksum = inet_chksum (tehdr, q->len);
  ICMP_STATS_INC (icmp.xmit);
  ip_output (q, NULL,
	     (struct ip_addr *) &(iphdr->src), ICMP_TTL, IP_PROTO_ICMP);
  pbuf_free (q);
}

#endif /* LWIP_ICMP */
